Unable to install this application because an application with the same identity is already installed

Nov 7, 2008 at 10:20 AM
Edited Dec 5, 2008 at 9:11 AM
The complete message is:

Unable to install this application because an application with the same identity is already installed. To install this application, either modify the manifest version for this application or uninstall the preexisting application.

I got this message on Vista SP1 + Office 2007 SP1 after:

  1. Uninstalling the VSTO ClickOnce manifest of Memba Velodoc Outlook Add-In;
  2. Uninstalling Memba Velodoc Outlook Add-In;
  3. Re-installing Memba Velodoc Outlook Add-In;
  4. Opening Outlook 2007 and getting the progress bar for the automatic installation by VSTO of the ClickOnce manifest.

This is a VSTO ClickOnce message which you get when teh CLickOnce cache is corrupted. It is not a Velodoc Add-In defect. I have tried several times to re-install without success.

The workaround is to clear the ClickOnce cache of application manifests before reinstalling by executing:
C:\Program Files\Microsoft.NET\SDK\v2.0\Bin\Mage.exe -cc

More information on Mage.exe at http://msdn.microsoft.com/en-us/library/acz3y3te(VS.80).aspx.

Sep 17, 2009 at 1:28 PM

Thanks a lot

Hi i am working on outlook add-in. I face the same problem while re-installing the add-in after make update in code and rebuild the setup.

 I have just completed my project with the help of your post